Manufacture of steel.



No Drawing.

seiner metal is amount of pi metal to preferably in WILLIIAM- n. WALKER,on NEW roan, N. Y.

,MANUFACTUBE OF STEEL.

foresee;

To all whom it may concern:

Be it known that I, WILLIAM R. WALKER, of the borough of Manhattan,in'the city of New York, county have invented an mprovement in theMannfacture of Steel, of which the following is a Specification. I

In the practice of my invention, I introduce molten pig metal into aBessemer converter and blow 'it has been eliminated and the carbonreduced to a definite percentage, preferably to about .05 per cent,which percentage can be gaged with accuracy because it is about thepercentage contained in themetal at the time when the flame drops, aphenomenon which is well known and readily recognized by the skilledblower. I then add to the desiliconized and substantially decarburizedmetal a proportion of carbon suflicient to raise its carbon content to adefinite percent. age, preferably to about .3 per cent, though thispercentage may be varied. The carbon addition is preferably made byadding to the Bessemer metal in. theladle pig iron either in the form ofcold pig or molten pig, and as the percentage of carbon of theBessubstantially constant, the be added in the ladle can be readi ydetermined with substantial precision. The carbon'may be introduced byadding anthracite coal or powdered coke to the metal instead of addingcarbon in the form'of-pig iron. If pig iron is added, it is the moltencondition. metal thus enriched in carbon is then charged into anelectrically heated furnace where it is treated preferably with basicadditions for removal of sulfur and phosphorus, and for increase of itsheat to bring it into the refined and heated condition proper forcasting into the ingot molds.

The importance of adding carbon to the blown metal before introducingitinto the electric furnace is that in this way the loss by skulling islessened, and by bringin the -metal to a definite carbon content thecats furnace are made uniform in the product renthe manufacture in theelectric character and duration, deredmore uniform and greatlyfacilitated.

As the decarburized metal is low in carand State of New York,'

the-rein until the silicon.

The

p Specification of Letters Patent.

Application filed June 18, 1909. Serial No. 502,865

f nnissunn tent is rendered easy by centage,

. Patented Jan. 9, 1912.

bon whentaken from the converter and is often transferred a considerabledistance to the electric furnace, a considerable amount of this metalwill solidify in the ladle and form skulls therein. This skulling actionwill reduce the amount of metal poured into the electric furnace fromthe ladle, and as the skulling action will vary, the amount poured inwill vary.- By adding carbon to the metal before its being carried tothe electric furnace, I raise its carbon content and thus also itsmelting point, and hence prevent or greatly lessen the amount ofskulling during the transfer to the electric furnace. This, therefore,makes the charges more uniform'in amount as poured into the electricfurnace.

The-obtaining of a ,uniform carbon conadding carbon to the blown metalrather than by attempting to stop the blow at the desired point, for todetermine the point of stopping before the flame drops is verydifficult, while to add the necessary-- percentage of carbon to the bathdepleted ofcarbon is easy.

I am aware that it is old-to eliminate practically all ofthe carbon andsteel before recarburizing and. do, not desire to claim this, but I ingprior to transferring thefimetal to the electric furnace.

The best percentage of carbon to be added will be governed somewhat bythe period 50f;

time. during which the metal is 'to be held in the ladle before pouringinto theelectric furnace, being greater as the time is longer. I claim:-1 In the manufacture of steel, the steps consisting of removingthecarbon of pig iron to a subst-antially, definite percentage, then,re'carburizing to a sufficient extent to lessen skulling duringtransfer, and then transferring the metal to and treating it in anelectric? furnace. 1

2. In the manufacture of steel, the steps consisting in-bessemerizingpig iron,,reducingits carbon to a substantially definite perth'en addingcarbon to a sufiicient extent to lessen skulling during transfer, andthen transferring the metal to and treating it in an electr1c furnace.

3. In the manufacture of steel, the steps do desire to claim therecarburiz-' s'rn'rns PATENT ormon'.

consisting of bessemerizing pig iron to 1 In testimeny whereof, I havehereunto set point where the flame drops, then removing my hand. themetal from the converter, adding carbon thereto to a suflicient extentto lessen skull- 5 ing during-transfer, and transferring .iiheWitnesses:

metal to and treating it in an electric fur- ALFRED T. DUFFIELD, nace.CLARENCE 'D. KERR.

WILLIAM RQWALKER.

